Answer:
La cantidad de yodo en la muestra es 0.217 g
Explanation:
Los parámetros dados son;
Normalidad de la solución de Na₂S₂O₃ = 0.1 N
Volumen de la solución de Na₂S₂O₃ = 17.1 mL
Masa de muestra = 0.376 g
La ecuación de reacción química se da de la siguiente manera;
I₂ + 2Na₂S₂O₃ → 2 · NaI + Na₂S₄O₆
Por lo tanto, el número de moles de sodio por 1 mol de Na₂S₂O₃ en la reacción = 1 mol
Por lo tanto, la normalidad por mol = 1 M × 1 átomo de Na = 1 N
Por lo tanto, 0.1 N = 0.1 M
El número de moles de Na₂S₂O₃ en 17,1 ml de solución 0,1 M de Na₂S₂O₃ se da de la siguiente manera;
Número de moles de Na₂S₂O₃ = 17.1 / 1000 × 0.1 = 0.00171 moles
Lo que da;
Un mol de yodo, I₂, reacciona con dos moles de Na₂S₂O₃
Por lo tanto;
0,000855 moles de yodo, I₂, reaccionan con 0,00171 moles de Na₂S₂O₃
La masa molar de yodo = 253.8089 g / mol
La masa de yodo en la muestra = 253.8089 × 0.000855 = 0.217 g.
Another name for a statovolcano is a _____ volcano because it is made of alternating layers of thick, sticky lava and volcanic rock and ash. A. shield B. cinder C. composite D. pyroclastic
Answer:
Bcinder
Explanation:
can periodic table indicates occurrance of the elements, why?
Answer: No
Explanation:
A periodic table can be defined as the table in which the row of chemical elements are present. All the elements of the row have same number of electron shells.
The arrangement of elements is based on atomic numbers, electron shell model and other chemical properties. The elements are placed in increasing order of atomic number.
This table does not give information about the occurrence of the elements.
if the balloon is 67,000 L at STP, what volume would it be if the air temperature cool to10.0°C in the pressure dropped to 99.2kPa as the balloon went higher?
Answer: The volume is 70872 L
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,
[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas (STP) = 1 atm
[tex]P_2[/tex] = final pressure of gas = 99.2 kPa = 0.98 atm (1kPa=0.0098atm)
[tex]V_1[/tex] = initial volume of gas = 67000 L
[tex]V_2[/tex] = final volume of gas = ?
[tex]T_1[/tex] = initial temperature of gas (STP) = 273K
[tex]T_2[/tex] = final temperature of gas = [tex]10.0^0C=(273+10)K=283K[/tex]
Now put all the given values in the above equation, we get:
[tex]\frac{1\times 67000}{273}=\frac{0.98\times V_2}{283}[/tex]
[tex]V_2=70872L[/tex]
Thus the volume is 70872 L
Name two drying agents that can be use to dry hydrogen gas
Which symbol can be used to indicate the pressure at which a chemical reaction is carried out?
25°C
2 atm
Pt
Answer:
2atm symbol can be used to indicate the pressure at which a chemical reaction is carried out
Which sentence is a scientific statement? A. There is a substance around us that cannot be detected. B. Kids should go to school for 12 years. C. Experimentation is the best way to obtain knowledge. D. Unicorns once existed on Earth. E. There are no living things on the Moon
Answer:
Experimentation is the best way to obtain knowledge.
Explanation:
This is a statement and it is scientific
Answer:
e
Explanation:
Question 4 (higher question)
Electrolysis of acidified water can produce hydrogen and oxygen.
The apparatus for the electrolysis is:
. water containing some dilute sulfuric acid
• two graphite rods
• a suitable container for the electrolysis reaction
. a suitable source of electricity
• test tubes
Describe how to use the apparatus to electrolyse acidified water, and how to test the gases to
show that they are hydrogen and oxygen. Include a diagram in your answer. [6 marks]
Answer:
Explanation:
Describe means you should recall facts, events or processes accurately. You might need to give an account of what something looked like, or what happened.
Explain means you need to make something clear, or state the reasons for something happening.
Compare means you need to describe similarities and differences between things. If you are asked to compare X and Y, write down something about X and something about Y, and give a comparison. Do not just write about X only or Y only.
Evaluate means you must use information supplied, or your own knowledge, to consider the evidence for and against or to identify strengths and weaknesses. You must then complete your answer with a conclusion, stating which is better and why, for example.
What does "A" represent in a the standard form of a double replacement reaction? a.) otion b.) cation
Answer: cation
Explanation:
"A" represent in a cation in the standard form of a double replacement reaction. Therefore, option B is correct.
What is cation ?Positively charged ions are known as cations. Negatively charged ions are known as anions. Ions are positively or negatively charged atoms or molecules. A balanced atom will become a positively charged cation if one or more electrons are lost.
In an electrical field, these ions are known as "cations" because they are positively charged and migrate toward the negative electrode (cathode).
The double-replacement reaction generally take up the form of AB + CD → AD + CB where A and C are positively-charged cations and B and D are negatively-charged anions.
Thus, option B is correct.
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Explain Redox tiltration and examples of half - life reactions.
Answer:
Explanation:
Half life reactions take place in electrochemistry where u have to find the emf generated from a cell
E.g Mg(s)/Mg(aq)//Ag(aq)/Ag(s)
2 Points
A student blows a whistle. In which direction do the air particles vibrate with
respect to the direction the sound wave travels?
A. Perpendicular to
B. Parallel to
C. At a 45 degree angel to
D. At an unpredictable angel
Answer:
parallel to
Explanation:
In parallel direction the air particles vibrate with respect to the direction the sound wave travels. The correct option is B.
What is sound wave?A sound wave is the pattern of disturbance caused by the movement of energy as it propagates away from the source of the sound through a medium (such as air, water, or any other liquid or solid matter).
Sound waves are produced by object vibrations and pressure waves, such as a ringing cellphone.
Because sound waves are produced by compressions and rarefactions in the air, they are referred to as longitudinal waves. The air particles vibrate in a direction parallel to the propagation direction.
The particles in a longitudinal wave are displaced parallel to the direction of the wave. Compressions moving along a slinky are an example of longitudinal waves.
Air particles vibrate in a parallel direction to the direction of travel of the sound wave.
Thus, the correct option is B.
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URGENT!!!!
An ordered list of chemical substances is shown.
Which substances in the list can be some of the reactants and products in the same combustion reaction? (4 points)
Select one:
a. 1, 2, and 3
b. 2, 3, and 6
c. 1, 4, and 5
d. 1, 2, and 5
Answer : The correct option is (b) 2, 3, and 6
Explanation :
Combustion reactions: It is defined as the reactions in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water.
A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.
The general chemical equation for the combustion is as follows:
[tex]C_xH_yO_z+O_2\rightarrow CO_2+H_2O[/tex]
where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.
The reactants and products in the same combustion reaction are [tex]O_2[/tex] and [tex]CO_2,H_2O[/tex] respectively.
Hence, the correct option is (b) 2, 3, and 6
Can Chlorine be harmful to any of the earth’s ecosystems? If so how?
Answer:
Although chlorine itself usually does not cause environmental harm, it combines rapidly to form chemicals such as dioxins that pollute water, contaminate fish and transfer to humans and larger animals that eat the fish.
Explanation:
If 119.5 g of iron is mixed with 279.50 g of copper (II) nitrate, what is the limiting reagent for the reaction?
Answer:
Copper ii nitrate is the limiting reagent
Explanation:
The first thing to write here is the equation of reaction;
Fe + Cu(NO3)2 ——> Fe(NO3)2 + Cu
When we talk of limiting reagent, we mean the reactant that is totally consumed upon the completion of the chemical reaction
To get the limiting reagent, we can know this by calculating the mass of a specific product formed from each of the masses of the reactants
Now, we can use the amount of copper solid deposited by each of the reactants to know the limiting reagent here.
Since the mole ratio in all cases is 1 to 1, this will be easy
For the iron, the number of moles reacted is mass of iron/ atomic mass of iron
That would be 119.5/56 = 2.134 moles
Now since the mole ratio is 1 to 1, 2.134 moles of copper will be formed
Thus, the mass of copper produced from the iron will be number of moles * atomic mass of copper = 2.134 * 64 = 136.57g
Now from the nitrate, the number of moles is
mass mixed/ molar mass of copper nitrate
molar mass of copper nitrate is 188g/mol
number of moles is thus 279.5/188 = 1.487 moles
Since the mole ratio is 1 to 1, it means that the number of moles of copper produced too is 1.487 moles
The mass of copper produced from this is number of moles of copper * atomic mass of copper
That will be 1.487 * 64 = 95.15g
Now, since the copper nitrate produces less amount of copper solid, it is the the reagent to be consumed first and thus it is our limiting reagent
Which of the following best describes why a cruise ship floats?
A. It displaces an equal or greater amount of water than its own
weight.
B. It displaces more than half of its weight in water.
C. Its volume and mass are equal.
D. Its volume is greater than its mass.
Answer:
A. It displaces an equal or greater amount of water than its own weight.
Explanation:
PLS HELP ! 5.00 mL of a stock solution, containing 0.200 M of Na3PO4 was pipetted into a 25.00 mL volumetric flask and made up to the calibration mark with deionised water. A serial dilution was carried out for another two times to obtain the final solution of desired concentration. Calculate the concentration of the final solution, express in ppm (by volume).
Answer:
262 ppm of Na₃PO₄
Explanation:
In a dilution, the concentration of the initial solution is decreased. When you take 5.00mL of the solution that is diluted to 25.0mL The solution is diluted 25/5 = 5 times
If you make another two serial dilutions the final solution wil decrease its concentration 5*5*5 = 125 times
As original solution containing 0.200 M of Na3PO4, the final solution will have a concentration of:
0.200M / 125 = 1.6x10⁻³M
Molarity is defined as the ratio between moles and liters. 1.6x10⁻³ moles of Na3PO4 in 1L are:
1.6x10⁻³mol ₓ (164g/mol) = 0.262g Na₃PO₄ / L
Assuming density of Na3PO4 as 1g/mL the concentration of the solution is:
0.262mL Na₃PO₄ / L
As 1mL = 1000μL:
262μL Na₃PO₄ / L
μL of solute per L of solution is equal to ppm, that means the solution has:
262 ppm of Na₃PO₄84. A salution of a substance x is used
of a
for
il Name the sulsstance 'x' and the
white kashing
write its farmula
il y Write the reaction the substance
la' named in il above with water.
of
dne
Answer:
Following are the answer to this question:
Explanation:
(1) Calcium oxide (CaO) is also referred to as quicklime. It is the solution for the substance used for whitewashing.
Whenever it reacts with water ([tex]H_2O[/tex]) and absorbs carbon dioxide ([tex]CO_2[/tex]), it then formed calcium carbonate ([tex]CaCO_3[/tex]), which produced a hard laminate on the walls, to first be whitened by the production of calcium hydroxide (CaOH).
(2) Slackened lime or calcium hydroxide arises whenever the fast limestone reacts with water.
[tex]CaO(s) + H_2O(l) \rightarrow Ca(OH)_2(aq).[/tex]
NEED HELP! An experiment _____. must always be done in a laboratory is best done if only one variable is tested for at a time can be done only by direct observation must always be done in the field
Answer:
Chemically
in chemistry
How many grams of H2S is needed to produce 18.00g of PbS if the H2S is reacted with an
excess (unlimited) supply of Pb(CH3COO)2?
Answer:
2.56 grams of H₂S is needed to produce 18.00g of PbS if the H2S is reacted with an excess (unlimited) supply of Pb(CH₃COO)₂
Explanation:
The balanced reaction is:
Pb(CH₃COO)₂ + H₂S → 2 CH₃COOH + PbS
By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction) they react and produce:
Pb(CH₃COO)₂: 1 moleH₂S: 1 moleCH₃COOH: 2 molesPbS: 1 moleIn this case, to know how many grams of H₂S are needed to produce 18.00 g of PbS, it is first necessary to know the molar mass of the compounds H₂S and PbS and then to know how much it reacts by stoichiometry. Being:
H: 1 g/moleS: 32 g/molePb: 207 g/moleThe molar mass of the compounds are:
H₂S: 2* 1 g/mole + 32 g/mole= 34 g/molePbS: 207 g/mole + 32 g/mole= 239 g/moleSo, by stoichiometry they react and are produced:
H₂S: 1 mole* 34 g/mole= 34 gPbS: 1 mole* 239 g/mole= 239 gThen the following rule of three can be applied: if 239 grams of PbS are produced by stoichiometry from 34 grams of H₂S, 18 grams of PbS from how much mass of H₂S is produced?
[tex]mass of H_{2} S=\frac{18 grams of PbS*34 grams of H_{2}S }{239 grams of PbS}[/tex]
mass of H₂S= 2.56 grams
2.56 grams of H₂S is needed to produce 18.00g of PbS if the H2S is reacted with an excess (unlimited) supply of Pb(CH₃COO)₂
Jaiden is writing a report about the structure of the atom. In her report, she says that the atom has three main parts and two subatomic particles. Do you agree with her? Why or why not?
Answer:
The smallest constituent of an element is termed as an atom. According to Jaiden, an atom comprises two subatomic particles and three prime parts, however, this is incorrect as an atom comprises three subatomic particles and two main parts. The three subatomic particles are the protons, electrons, and neutrons. All these parts are smaller in comparison to an atom, thus, they are considered as subatomic particles.
To be considered as an atom, an atom is needed only electrons and neutrons, like hydrogen exhibit one electron and one proton. On the other hand, the overall charge of the atom is not affected by the presence of neutrons, it is the subatomic particle that only enhances the mass of the atom.
Answer:
I disagree with her because an atom has two main parts: the nucleus and the electron cloud. Atoms have three subatomic particles: protons, neutrons, and electrons.
Explanation:
PLEASE HURRRYYYY
A buffer is made using HCO2Na. Which other substance should the buffer contain?
HCO2Li
HCO2H
NaNO3
HCl
Answer:
HCO₂H
Explanation:
A buffer is defined as the mixture between a weak acid and its conjugate base, or vice versa, in an aqueous solution.
The HCO₂Na (Sodium formate), is the conjugate base of formic acid, HCO₂H, a weak acid of pKa = 3.75.
Thus, to make a buffer using HCO₂Na, the other substance the buffer should contain is HCO₂H
Answer:
HCO₂H
Explanation:
Keeping in mind the rules for significant dig-
its, what is the product of 0.6906 m and 4.03
m?
Answer:
2.78
Explanation:
When multiplying, your answer will have the same amount of sig figs as the multicand or multiplier that has the lower number of sig figs. In this case, 4.03 is the one with the lowest number of sigs figs, which is 3 sig figs, so the answer should have 3 sig figs, so the answer is 2.78.
What is Charles’s law? State the definition of the law in words. What are the assumptions of Charles’s law? Write mathematical equations that represent the law. What can you do with Charles’s law? Using a gas-filled balloon as an example, describe what happens to the gas molecules that behave according to Charles’s law.
Answer:
The volume of a given mas of a gas is directly proportional to the temperature if the pressure remains constant
V is directly proportional to T
V=1/T
V=constant/T
Explanation:
Charles law states that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature, if the pressure remains constant.
e.g., In winters as the temperature falls off, when you take a basketball outside in the ground the ball shrinks.
The mathematical equation that represents Charles law:
V₁/T₁ = V₂/T₂
where, V₁ = initial volume
T₁ = initial absolute temperature
V₂ = final volume
T₂ = final absolute temperature
The applications of Charles law has in daily life are:
Helium balloons shrinks in a cold weather.The capacity of the human lung decreases in winter season. This makes difficult for the athletes to perform in winter season and it also makes it difficult for people to go jogging.A gas-filled balloon experiment:
If a balloon is filled with air, it will shrink when cooled and the balloon expands if heated. This happens because the air inside the balloon, which is a gas molecules, occupies a smaller volume when it is cool, and occupies a larger volume when it is hot.
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Calculate the molar mass of CH4 gas at STP when 5.46Lof the gas weighs 4g??
Answer:
About 16.42 grams
Explanation:
[tex]PV=nRT \\\\(1)(5.46L)=n(0.0821)(273) \\\\n\approx 0.2436 \\\\4g/0.2436\approx 16.42[/tex]
Hope this helps!
Which of these observations are not explained by kinetic-molecular theory?
The question's incomplete unfortunately, which observations?
Answer:
At very low temperatures, gases expand less for a given pressure change than they do at high temperatures
Cu+2AgNO
3
→2Ag+Cu(NO
3
)
2
start text, C, u, end text, plus, 2, start text, A, g, N, O, end text, start subscript, 3, end subscript, right arrow, 2, start text, A, g, end text, plus, start text, C, u, left parenthesis, N, O, end text, start subscript, 3, end subscript, start text, right parenthesis, end text, start subscript, 2, end subscript
How many grams of \text{Ag}Agstart text, A, g, end text will be produced from 19.0 \text{ g}19.0 g19, point, 0, start text, space, g, end text of \text{Cu}Custart text, C, u, end text and 125 \text{ g}125 g125, start text, space, g, end text of \text{AgNO}_3AgNO
3
start text, A, g, N, O, end text, start subscript, 3, end subscript?
Answer:
Mass of Ag produced = 64.6 g
Note: the question is, how many grams of Ag is produced from 19.0 g of Cu and 125 g of AgNO3
Explanation:
Equation of the reaction:
Cu + 2AgNO3 ---> 2Ag + Cu(NO3)2
From the equation above, 1 mole of Cu reacts with 2 moles of AgNO3 to produce 2 moles of Ag and 1 mole of Cu(NO3)2.
Molar mass of the reactants and products are; Cu = 63.5 g/mol, Ag = 108 g/mol, AgNO3 = 170 g/mol, Cu(NO3)2 = 187.5 g/mol
To determine, the limiting reactant;
63.5 g of Cu reacts with 170 * 2 g of AgNO3,
19 g of Cu will react with (340 * 19)/63.5 g of AgNO3 =101.7 g of AgNO3.
Since there are 125 g of AgNO3 available for reaction, it is in excess and Cu is the limiting reactant.
63.5 g of Cu reacts to produce 108 * 2 g of Ag,
19 g of Cu will react to produce (216 * 19)/63.5 g of Ag = 64.6 g of Ag.
Therefore mass of Ag produced = 64.6g
Which element is needed for
a. Bone and teeth formation.
b. Treatment of water.
Answer:
a.calcium
b.chlorine
Another chemistry question. Help me!
To prepare 250cm³ of standard solution of 1.0 mol dm-³ sodim carbonate Na2Co3
Answer:
Molar mass Na2CO3 = 2*23 + 12 + 3*16 = 106 g/ mol
Mass of 1 mol Na2CO3 = 106 g
mass (Na2CO3) = 106g*250cm³/1000cm³ = 26.5 g
1) It is necessary because all Na2CO3 will be in the solution, and no Na2CO3 would be lost.
2) Because the solution that was formed after rinsing beaker contains Na2CO3.
3) Eyes should be on the level of calibration mark of the volumetric flask.
4) It is necessary to prevent evaporation of water, and changing , because of it, the concentration of the solution.
so ...this is the question and I hope you get it right one
Answer:
About 96 grams per mole
Explanation:
The chemical formula of ammonium carbonate is [tex](NH_4)_2CO_3[/tex]. This means that breakdown of moles of atom per mole of molecule is:
2 moles of nitrogen, with a molar mass of around 14
8 moles of hydrogen, with a molar mass of around 1
1 mole of carbon, with a molar mass of about 12
3 moles of oxygen, with a molar mass of about 16
The molar mass of ammonium carbonate is therefore:
2(14)+8(1)+1(12)+3(16)=28+8+12+48=about 96
Hope this helps!
5. What volume would you need to dilute 0.2 L of a 15 M solution to obtain a 3 M
solution?
Answer:
IL
Explanation:
M_1 V_1 = M_2 V_2
M_1 = 15 M
V_1 = 0.2 L
M_2 = 3 M
V_2 = ?
15 x 0.2 = 3V_2
15 x 0.2 = 3
3 / 3V_2
1 L= V_2
1 L is the volume that would be needed to dilute 0.2 L of a 15 M solution to obtain a 3 M solution.
What is volume?A measurement of three-dimensional space is volume. It is frequently expressed quantitatively in SI-derived units, other imperial units, or US customary units. Volume and the notion of length are connected. In contrast to how much space the container actually occupies, the overall size of a container is typically thought of as its capacity, or the quantity of fluid it could hold.
Volume was initially measured using naturally occurring vessels of a comparable shape and then with standardised containers. Arithmetic formulas can be used to quickly calculate the volume of several straightforward three-dimensional shapes.
Molarity₁×Volume₁=Molarity₂×Volume₂
15 x 0.2 = 3×Volume₂
15 x 0.2 = 3
3 / 3=Volume₂
1 L=Volume₂
Therefore, 1 L is the volume that would be needed to dilute 0.2 L of a 15 M solution to obtain a 3 M solution.
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whats the chemical formula for dilute hydroxide acid